There are methods for collecting printed products in which the printed products are collected on a collection section. In this process the individual printed sheets or inserts are in each case provided by feeders, then drawn off and finally transferred to the collection section. In the known methods the collection section comprises conveyors, e.g. conveyor belts, which transport the drawn-off printed sheets for further processing.
European Patent Application EP 0588764 discloses a means for collating printed products, which means consists on the one hand of a loading station for feeding covers or cover products into a rotating conveying mechanism, and on the other hand of a supply station for feeding inserts, i.e. printed sheets, into the specified cover products. The end products thus formed, which consist of a cover product and a number of inserts, are taken out of the rotating mechanism by an extraction station and transported to a machine for further processing.
When collecting printed sheets, the aspect of dealing with any defects which arise when drawing off printed sheets from the feeders is particularly important, as this has a considerable impact on the quality and/or processing time for collecting printed sheets in order to produce the end product. Defect handling is therefore an important aspect of such a collection process.
In many existing methods defective products are simply removed, the term “product” in the context of the present invention referring to a collection of printed sheets, and the term “defective” referring to an incomplete, assembled product. The disadvantage of such methods is the high wastage as in most cases the rejected products cannot be re-used. European Patent Application EP 2 107 023 represents a further development in that it discloses a method and a device for conveying flat products. Defective products are not removed in this process, as was the case previously, but are fed back into the collection section by means of a revolving conveyor, completed in this section and then passed on for further processing. The disadvantage of this solution is the complicated system for returning the defective end products, which makes the system more expensive.